The 2015 Nobel Prize Shared by Two Physicists

Awarded for their discoveries about Neutrinos, Takaaki Kajita from University of Tokyo and Arthur B. McDonald of Queen’s University in Canada, together, won the Nobel Prize in Physics on Tuesday Oct 6, 2015. They share a prize of $960,000 awarded by the The Royal Swedish Academy of Sciences. The two scientists join the ranks of of recipients since the Nobel Prize began in 1901.

Neutrinos are very mysterious and nearly invisible. In 1956 Neutrinos were proven to exist by Frederick Reines and Clyde Cowan; since that time, physicists and cosmologists have been trying to learn more about them and how to control them.

Dennis Overbye of New York Times describes the important work of Takaaki Kajita and Arthur B. McDonald that led to their Nobel Prize award. He had the following to say:

“The ghostly neutrino — it means “small neutral one” in Italian — carries no electric charge and is so light that it had been assumed for many years to have no mass at all. The scientists showed that neutrinos, which are found in three “flavors,” could oscillate from one flavor to another — changing identities as they traveled through the atmosphere or through space from the sun — demonstrating that they have mass.

Kajita was part of a team of researchers who in 1998 discovered that neutrinos from the atmosphere switched between two identities on their way to the Super-Kamiokande detector, nearly two-thirds of a mile below the Earth’s surface.

In 1999, McDonald announced that neutrinos from the sun were not disappearing, but merely changing disguises, on their way to Earth. He and his colleagues had captured the neutrinos using a uniquely sensitive new detector 6,800 feet below ground, at the Sudbury Neutrino Observatory, which is part of Queen’s University in Kingston, Ontario.”

“Many neutrinos are created in reactions between cosmic radiation and the Earth’s atmosphere. Others are produced in nuclear reactions inside the Sun. Thousands of billions of neutrinos are streaming through our bodies each second. Hardly anything can stop them passing; neutrinos are nature’s most elusive elementary particles…

…New discoveries about their deepest secrets are expected to change our current understanding of the history, structure and future fate of the universe.”

According to Jennifer Ouellette of Gizmodo, In 1930 Wolfgang Pauli came up with a theory of these invisible particles; Decades later, physicists finally observed and proved the existence of neutrinos, and this proved Wolfgang Pauli’s theory was correct.

Over the years, many scientists have won the Nobel Prize in Physics for discoveries related to neutrinos.